JP2006041042A - Collimation structure for laser diode and optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collimation structure for a laser diode that can easily adjust an optical axis and the tilt of it, and shorten the operation time needed to assemble a device. <P>SOLUTION: The collimation structure is equipped with a housing 11, a cradle 15 which is held movably along one surface 11a of the housing 11, a laser diode holder 16 which is held tiltably by the cradle 15 and supports the laser diode 14, and 1st and 2nd pressure plates 17 and 18 which press those cradle 15 and laser diode holder 16 against the housing 11 to hold them movably. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical axis adjustment structure of a laser diode and an optical pickup device applied as a light source of an optical pickup, for example.

  In the present invention, “substantially center” includes “center”, and “substantially along the virtual spherical surface” includes “along the virtual spherical surface”.

Compact disc (abbreviated CD: Compact Disk), digital versatile disc (abbreviated DVD: Digital Versatile Disk) and Blu-ray disc (abbreviated BD: Blu)
An optical pickup device for recording, reproducing and erasing information on a recording medium such as a (Ray Disk) has been put to practical use. A laser diode is applied as a light source of this optical pickup device (see, for example, Patent Document 1). FIG. 7 is a plan view showing the main part of the optical axis adjustment structure of the conventional optical pickup device, and FIG. 8 is a side view showing the main part of the optical axis adjustment structure of the conventional optical pickup device.

  The optical pickup device includes a housing 1, a laser diode cradle 2, a pressing plate 3 made of a spring material, a laser diode holder 4, and a laser diode 5. A laser diode 5 is fixed to the laser diode holder 4 using an adhesive or the like. The laser diode holder 4 is provided with a partial spherical contact portion (referred to as a spherical contact portion). The laser diode cradle 2 is formed with a spherical seat that comes into contact with the spherical contact portion.

  The laser diode holder 4 and the laser diode cradle 2 are fixed with four screws 6. The optical axis is tilt-adjusted by tightening or loosening the four screws 6. The laser diode cradle 2 is held by a press plate 3 so as to be movable with respect to the housing 1. As a result, the optical axis on the plane of the laser diode 5 is adjusted.

JP-A-5-81693

  In the conventional optical axis adjustment structure, the optical axis adjustment on the plane and the inclination adjustment of the optical axis must be sequentially performed. Further, the adjustment of the tilt of the optical axis takes time for the adjustment itself by tightening and loosening the screw 6. Therefore, in the conventional optical axis adjustment structure, the optical axis adjustment and the optical axis tilt adjustment cannot be easily performed, and the assembly time of the apparatus becomes long.

  An object of the present invention is to provide an optical axis adjustment structure of a laser diode that can easily adjust the optical axis and the inclination of the optical axis and can reduce the work time required for assembling the apparatus. .

The present invention includes a housing;
A laser diode support means capable of supporting a laser diode;
An optical axis adjustment structure for a laser diode, characterized in that the housing has pressing means for pressing and holding the laser diode support means so as to be movable.

  According to the present invention, the optical axis adjusting structure has a housing, a laser diode support means, and a pressing means. The laser diode support means can support the laser diode. The pressing means presses and holds the laser diode support means on the housing so as to be movable. When the laser diode and the laser diode support means are to be moved, in other words, when they are to be adjusted, the following operations are performed. The laser diode support means is always pressed against the housing by the pressing force of the pressing means and moves relative to the housing. The laser diode support means can be moved a predetermined small distance with respect to the housing without being affected by the pressing force. In this way, the optical axis of the laser diode is adjusted.

  According to the present invention, the laser diode support means includes: a pedestal that is movably held along one surface portion of the housing; and a laser diode holder that is tiltably held on the pedestal and supports the laser diode. It is characterized by providing.

  According to the invention, the laser diode support means comprises a cradle and a laser diode holder. The cradle is held movably along one surface portion of the housing. The laser diode holder is tiltably held on the cradle and supports the laser diode. This adjusts the optical axis of the laser diode and the tilt of the optical axis.

  According to the present invention, the laser diode holder is formed with one curved surface portion facing the cradle and another curved surface portion facing the pressing means, and the one curved surface portion and the other curved surface portion are substantially centered on the light emitting point of the laser diode. It is characterized by being formed substantially along a virtual spherical surface.

  According to the invention, the curved surface portion and the other curved surface portion are formed in the laser diode holder. The one curved surface portion and the other curved surface portion are formed substantially along a virtual spherical surface having the light emitting point as a center. The one curved surface portion faces the cradle, and the other curved surface portion faces the pressing means. The other curved surface portion is pressed and held by the pressing means, and the one curved surface portion is tilted in contact with the cradle.

  Further, the present invention is characterized in that the curvature radius is different between the one curved surface portion and the other curved surface portion of the laser diode holder.

  According to the present invention, since the radius of curvature of one curved surface portion and the radius of curvature of the other curved surface portion are different, the following operation is achieved. The curvature radius of the curved surface portion facing the cradle can be made constant, and the curvature radius of the other curved surface portion facing the pressing means can be variously changed to obtain an optimal curved surface portion shape for the pressing means and the laser diode. On the contrary, the curvature radius of the other curved surface portion is made constant, and the curvature radius of the one curved surface portion can be variously changed to obtain the optimal curved surface portion shape for the cradle.

  Further, the present invention is characterized in that the other curved surface portion of the laser diode holder is formed to have a larger radius of curvature than the one curved surface portion.

  According to the present invention, the curvature radius of the one curved surface portion of the laser diode holder in contact with the cradle is made smaller than the curvature radius of the other curved surface portion. In other words, the other curved surface portion has a larger radius of curvature than the one curved surface portion. Moreover, the other curved surface portion determines the radius of curvature based on the size of the laser diode and the like. The other curved surface part is formed so that the radius of curvature is larger than that of one curved surface part. Therefore, when adjusting the tilt of the optical axis, increase the amount of movement when moving the laser diode holder relative to the cradle. Can do.

  According to the present invention, the cradle is characterized in that a contact surface facing one curved surface portion of the laser diode holder is formed in a conical surface shape.

  According to the present invention, the contact surface of the cradle facing the one curved surface portion of the laser diode holder is formed in a conical surface shape, thereby achieving the following action. A gap can be formed between the conical surface portion of the cradle and one curved surface portion of the laser diode holder.

The present invention also includes a housing,
A laser diode in which a cap part is formed in a partial spherical shape;
A laser diode optical axis adjusting structure characterized in that the housing has pressing means for pressing and holding the laser diode through the cap portion so as to be movable.

  According to the invention, the optical axis adjusting structure has a housing, a laser diode, and a pressing means. The cap portion of the laser diode is formed in a partial spherical shape. The pressing means presses and holds the laser diode movably on the housing via the cap portion. When the laser diode is to be moved, in other words, when it is to be adjusted, the following operation is performed. The laser diode is always pressed against the housing by the pressing force by the pressing means, and moves relative to the housing via the cap portion. The laser diode can be moved a predetermined small distance with respect to the housing without being affected by the pressing force. In this way, the optical axis of the laser diode is adjusted.

  Moreover, this invention is an optical pick-up apparatus provided with the optical axis adjustment structure of the said laser diode.

  According to the present invention, an optical pickup device having such an optical axis adjustment structure of a laser diode can be realized. The laser diode mounted on the optical pickup device can easily adjust the optical axis and the tilt of the optical axis with a simpler structure than the conventional structure, and can shorten the work time required for assembly.

  According to the present invention, the pressing means presses and holds the laser diode support means movably on the housing. When the laser diode and the laser diode support means are to be moved, in other words, to be adjusted, the following operations and effects are achieved. The laser diode support means is always pressed against the housing by the pressing force of the pressing means and moves relative to the housing. The laser diode support means can be moved a predetermined small distance with respect to the housing without being affected by the pressing force. In this way, the laser diode can be easily adjusted in optical axis and optical axis inclination with a simpler structure than the conventional structure. Therefore, the working time required for assembling the apparatus can be shortened compared to the prior art.

  Further, according to the present invention, the cradle is held movably along one surface portion of the housing. The laser diode holder is tiltably held on the cradle and supports the laser diode. In particular, since the laser diode holder is tiltably held on the cradle, the optical axis can be easily adjusted. In this way, the optical axis of the laser diode and the tilt of the optical axis can be adjusted. With such a simple structure, it is possible to easily adjust the optical axis and the inclination of the optical axis.

  According to the present invention, one curved surface portion of the laser diode holder faces the cradle, and the other curved surface portion on the opposite side faces the pressing means. The other curved surface portion is pressed and held by the pressing means, and the one curved surface portion is tilted in contact with the cradle. In this manner, the tilt of the optical axis of the laser diode can be adjusted while the laser diode holder is in contact with the cradle, and can be pressed by the pressing means to maintain the state after the tilt adjustment.

  Further, according to the present invention, since the curvature radius of one curved surface portion and the curvature radius of the other curved surface portion are different, the following effects can be obtained. The curvature radius of the curved surface portion facing the cradle can be made constant, and the curvature radius of the other curved surface portion facing the pressing means can be variously changed to obtain an optimal curved surface portion shape for the pressing means and the laser diode. On the contrary, the curvature radius of the other curved surface portion is made constant, and the curvature radius of the one curved surface portion can be variously changed to obtain the optimal curved surface portion shape for the cradle. Therefore, the design change becomes easy. Therefore, the time required for the design change can be shortened, and the manufacturing cost can be reduced.

  According to the present invention, the radius of curvature of the one curved surface portion of the laser diode holder in contact with the cradle is made smaller than the radius of curvature of the other curved surface portion. In other words, the other curved surface portion has a larger radius of curvature than the one curved surface portion. Moreover, the other curved surface portion determines the radius of curvature based on the size of the laser diode and the like. The other curved surface part is formed so that the radius of curvature is larger than that of one curved surface part. Therefore, when adjusting the tilt of the optical axis, increase the amount of movement when moving the laser diode holder relative to the cradle. Can do. The amount of relative movement of the laser diode holder required to adjust the tilt angle of the optical axis can be increased. As a result, it is possible to easily and quickly adjust the minute inclination of the optical axis.

  According to the present invention, the contact surface of the cradle facing the one curved surface portion of the laser diode holder is formed in a conical surface shape, thereby providing the following effects. A gap can be formed between the conical surface portion of the cradle and one curved surface portion of the laser diode holder. By applying an adhesive to the gap and curing it, the laser diode holder can be firmly fixed to the cradle.

  According to the invention, the pressing means presses and holds the laser diode movably on the housing via the cap portion. When the laser diode is to be moved, in other words, when it is to be adjusted, the following operations and effects are achieved. The laser diode is always pressed against the housing by the pressing force by the pressing means, and moves relative to the housing via the cap portion. The laser diode can be moved a predetermined small distance with respect to the housing without being affected by the pressing force. In particular, since the laser diode can be moved relatively and directly with respect to the housing via the cap portion, the number of parts can be significantly reduced as compared with the prior art. Other effects similar to those of the first aspect are obtained.

  Further, according to the present invention, an optical pickup device having such an optical axis adjustment structure of a laser diode can be realized. The laser diode mounted on this optical pickup device can easily adjust the optical axis and tilt of the optical axis with a simpler structure than the conventional structure, and can reduce the work time required for assembly. There are effects like this. The assembly of the entire optical pickup device and the shortening of the optical axis adjustment time can be achieved, and a higher quality optical pickup device than the conventional one can be realized.

FIG. 1 is a cross-sectional view of a main part of the optical pickup device 10 according to the first embodiment of the present invention viewed along a virtual plane including the optical axis L1. FIG. 2 is a plan view of a main part of the optical pickup device 10 according to the first embodiment. FIG. 3 is a side view showing the relationship among the housing 11, the laser diode support means 12, and the pressing means 13. An optical pickup device 10 (referred to as a first pickup device 10) according to the first embodiment includes a compact disc (abbreviated as CD) and a digital versatile disc (abbreviated as DVD: Digital).
Information is recorded on the recording surface of a recording medium by irradiating laser diode light onto a recording medium such as a Versatile Disk and a Blu-ray Disc (abbreviated as BD). It is applied to the device that reproduces.

  The first pickup device 10 includes a laser diode 14 as a light source, an optical axis adjustment structure, an optical system, an actuator, and a light receiving element. The optical axis adjusting structure is a structure for adjusting the optical axis L1 of the laser diode 14, and mainly includes the housing 11, the laser diode holder cradle 15, the laser diode holder 16, and the first and second presser plates 17. , 18 and pressing means. The laser diode holder cradle 15 is synonymous with “cradle”.

  A hole is formed in the housing 11 so as to secure at least an optical path from the laser diode 14. A pedestal 15 is held on the housing 11 so as to be movable by a pair of first pressing plates 17 along one surface portion 11 a of the housing 11. These first pressing plates 17 are arranged at a predetermined distance in the x direction indicated by the arrow x in FIGS. Each first presser plate 17 is made of an elastically deformable spring material. One end of the first presser plate 17 is fixed to the housing 11 by a screw 19 and the other end of each first presser plate 17 presses and holds the cradle 15. It is supposed to be. The middle portion of each first presser plate 17 in the x direction is bent at right angles to the one end and the other end and bent by the thickness of the cradle 15.

  The other end of the first presser plate 17 is notched in the x direction so that the other end does not interfere with a screw 20 for fixing a second presser plate 18 described later. In other words, the cradle 15 is movable along the one surface portion 11 a of the housing 11 while being held by being pressed against the housing 11 by the other end portions of the pair of first pressing plates 17. The x direction is a direction perpendicular to the thickness direction of the first pickup device 10 and is synonymous with a direction along the one surface portion 11a. In the vicinity of the middle of the cradle 15 in the x direction, a cradle hole that is continuous with the hole of the housing 11 is formed to secure an optical path.

  A laser diode holder 16 that is tiltably held on the cradle 15 and supports the laser diode 14 is provided. These cradle 15 and laser diode holder 16 correspond to laser diode support means. That is, the laser diode 14 can be supported by the cradle 15 and the laser diode holder 16. The laser diode holder 16 is formed with a cradle-side spherical convex portion 16a facing the cradle 15 and a presser plate-side spherical convex portion 16b facing the second presser plate 18. The cradle side spherical convex portion 16a corresponds to one curved surface portion, and the presser plate side spherical convex portion 16b corresponds to the other curved surface portion. The pedestal side spherical convex portion 16a and the pressing plate side spherical convex portion 16b are formed substantially along a virtual spherical surface having the light emitting point of the laser diode 14 as a substantial center. The cradle side spherical convex portion 16a and the pressing plate side spherical convex portion 16b are formed so as to have different radii of curvature. Specifically, the pressing plate side spherical convex portion 16b is formed to have a larger radius of curvature than the cradle side spherical convex portion 16a.

  The cradle 15 is formed with a spherical recess 15a that abuts on the cradle-side spherical protrusion 16a. The cradle side spherical convex portion 16a and the spherical concave portion 15a are configured to be slidable. A pair of second presser plates 18 are respectively fixed to the cradle 15 integrated with the housing 11 by screws 20. These second presser plates 18 are disposed slightly apart in the x direction. Each second presser plate 18 is made of an elastically deformable spring material, one end of which is fixed to the cradle 15 by the screw 20, and the other end is a presser plate side spherical convex portion 16 b of the laser diode holder 16. Is pressed and held. The laser diode holder 16 is tiltably held by the housing 11 and the cradle 15 by the pressing force of the second pressing plate 18.

  When the optical axis of the laser diode 14 is adjusted along the one surface portion 11a, the laser diode holder 16 is grasped by a catcher (not shown) of the optical axis adjuster, and the cradle 15, the second presser plate 18, the laser diode holder 16 and The laser diode 14 moves relative to the housing 11 in a state where the laser diode 14 is held on the housing 11 by the first pressing plate 17. When the inclination of the optical axis L1 of the laser diode 14 is adjusted, a rotational force about the light emitting point of the laser diode 14 is applied from this state (the state immediately after the optical axis adjustment) by the catcher of the optical axis adjuster. To do. The laser diode holder 16 and the laser diode 14 are held on the cradle 15, that is, the housing 11 by the second pressing plate 18, and the cradle-side spherical convex portion 16 a of the laser diode holder 16 and the spherical concave portion 15 a of the cradle 15 Slides. Thereby, the inclination of the optical axis L1 of the laser diode 14 is adjusted. After the adjustment is completed, even if the gripping by the catcher is released, the laser diode holder 16 and the cradle 15 maintain the adjusted posture by the first and second pressing plates 17 and 18. In a state where the post-adjustment posture is maintained, it is possible to shift to a bonding process which is a subsequent process. In the bonding step, the laser diode holder 16 is firmly fixed to the cradle 15 using an adhesive.

  According to the optical axis adjusting structure described above, the first and second pressing plates 17 and 18 hold the laser diode supporting means 12 so as to be movably pressed on the housing 11. When the laser diode 14 and the laser diode support means 12 are to be moved, in other words, to be adjusted, the following operations and effects are achieved. The laser diode support means 12 is always pressed against the housing 11 by the pressing force of the first and second pressing plates 17 and 18 and moves relative to the housing 11. The laser diode support means 12 can be moved by a predetermined small distance with respect to the housing 11 without being affected by the pressing force. Thus, the laser diode 14 can be easily adjusted in optical axis and optical axis inclination with a simpler structure than the conventional structure. Therefore, the working time required for assembling the apparatus can be shortened compared to the prior art.

  Further, the cradle-side spherical convex portion 16 a of the laser diode holder 16 faces the cradle 15, and the opposite presser plate-side spherical convex portion 16 b faces the second presser plate 18. The holding plate-side spherical convex portion 16 b is pressed and held by the second pressing plate 18, and the cradle-side spherical convex portion 16 a comes into contact with the spherical concave portion 15 a of the pedestal 15 and tilts. In this manner, the tilt of the optical axis L1 of the laser diode 14 can be adjusted while the laser diode holder 16 is in contact with the receiving table 15, and the pressure means is pressed to maintain the state after the tilt adjustment. be able to.

  In the laser diode holder 16, the radius of curvature of the cradle-side spherical convex portion 16a is different from the radius of curvature of the presser plate-side spherical convex portion 16b. The radius of curvature of the cradle-side spherical convex portion 16a facing the cradle 15 is made constant, and the radius of curvature of the presser-plate-side spherical convex portion 16b facing the second presser plate 18 is variously changed. It can be shaped. Therefore, the design change becomes easy. Therefore, the time required for the design change can be shortened, and the manufacturing cost can be reduced. When the curvature radius of the holding plate side spherical convex portion 16b is formed to be larger than the curvature radius of the receiving side spherical convex portion 16a, when the inclination of the optical axis L1 is adjusted, The amount of movement when the laser diode holder 16 is relatively moved can be increased. The relative movement amount of the laser diode holder 16 required to adjust the tilt angle of the optical axis L1 can be increased. As a result, it is possible to easily and quickly adjust the minute inclination of the optical axis L1.

  FIG. 4 is a cross-sectional view of a main part when an optical pickup device 10A according to the second embodiment of the present invention is cut along a virtual plane including the optical axis L1. FIG. 5 is an enlarged cross-sectional view showing a main part of the cradle 15A having a contact surface formed in a conical surface shape. However, the same members as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the optical axis adjustment structure of the optical pickup device 10A according to the second embodiment, the cradle 15A has a conical surface with a contact surface facing the cradle-side spherical convex portion 16a of the laser diode holder 16. Thus, a gap δ can be formed between the conical surface portion 15b of the cradle 15A and the cradle-side spherical convex portion 16a of the laser diode holder 16. By applying and curing an adhesive in the gap δ, the laser diode holder 16 can be firmly fixed to the receiving table 15A.

  FIG. 6 is a cross-sectional view of a main part when an optical pickup device 10B according to the third embodiment of the present invention is cut along a virtual plane including the optical axis L1. In the optical pickup device 10B according to the third embodiment, the optical axis adjustment structure of the laser diode 21 includes the housing 11, the laser diode 21, the laser diode holder 23, and the first and third presser plates as pressing means. 17 and 22. The cap part 21a of the laser diode 21 is formed in a partial spherical shape. The third presser plate 22 presses and holds the laser diode 21 movably on the laser diode holder 23 integrated with the housing 11 via the cap portion 21a. When the laser diode 21 should be moved, in other words, when it should be adjusted, the following operations and effects are achieved. The laser diode 21 is always pressed against the housing 11 by the pressing force of the third pressing plate 22, and moves relative to the housing 11 via the cap portion 21a. The laser diode 21 can be moved by a predetermined small distance with respect to the housing 11 without being affected by the pressing force. In this way, the optical axis of the laser diode 21 is adjusted. In particular, since the laser diode 21 can be moved relatively and directly with respect to the housing 11 via the cap portion 21a, the number of parts can be significantly reduced as compared with that of the prior art. Other effects similar to those of the first embodiment are obtained.

  As another embodiment of the present invention, the cradle-side spherical convex portion and the presser plate-side spherical convex portion may be formed so as to have the same radius of curvature. Contrary to the first embodiment, the radius of curvature of the cradle-side spherical convex portion can be made larger than the radius of curvature of the presser plate-side spherical convex portion.

It is sectional drawing of the principal part which looked at the optical pick-up apparatus 10 which concerns on the 1st Embodiment of this invention in the virtual plane containing the optical axis L1. It is a top view of the principal part of the optical pick-up apparatus 10 which concerns on 1st Embodiment. It is a side view showing the relationship between the housing 11, the laser diode support means 12, and the pressing means 13. It is sectional drawing of the principal part which looked at 10 A of optical pick-up apparatuses which concern on the 2nd Embodiment of this invention by the virtual plane containing the optical axis L1. It is sectional drawing which expands and shows the principal part of the receiving stand 15A in which the contact surface was formed in the shape of a conical surface. It is sectional drawing of the principal part which looked at the optical pick-up apparatus 10B which concerns on the 3rd Embodiment of this invention in the virtual plane containing the optical axis L1. It is a top view which shows the principal part of the optical axis adjustment structure of the conventional optical pick-up apparatus. It is a side view which shows the principal part of the optical axis adjustment structure of the conventional optical pick-up apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical pick-up apparatus 11 Housing 12 Laser diode support means 13 Press means 14 Laser diode 15 Receiving stand 16 Laser diode holder 16a Receiving side spherical convex part 16b Holding plate side spherical convex part 17, 18 1st and 2nd holding board

Claims (8)

A housing;
A laser diode support means capable of supporting a laser diode;
An optical axis adjustment structure for a laser diode, characterized in that the housing has pressing means for pressing and holding the laser diode support means so as to be movable.   The laser diode support means includes a cradle that is movably held along one surface portion of the housing, and a laser diode holder that is tiltably held by the cradle and supports the laser diode. The optical axis adjustment structure of a laser diode according to claim 1.   The laser diode holder is formed with one curved surface portion facing the cradle and another curved surface portion facing the pressing means, and the one curved surface portion and the other curved surface portion are substantially along a virtual spherical surface substantially centered on the light emitting point of the laser diode. The optical axis adjustment structure of a laser diode according to claim 2, wherein the optical axis adjustment structure is formed by:   4. The optical axis adjusting structure of a laser diode according to claim 3, wherein the one curved surface portion and the other curved surface portion of the laser diode holder have different radii of curvature.   4. The laser diode optical axis adjustment structure according to claim 3, wherein the other curved surface portion of the laser diode holder is formed to have a radius of curvature larger than that of the one curved surface portion.   6. The laser diode optical axis adjusting structure according to claim 3, wherein the cradle has a conical surface with a contact surface facing one curved surface of the laser diode holder. . A housing;
A laser diode in which a cap part is formed in a partial spherical shape;
An optical axis adjustment structure for a laser diode, characterized in that the housing has pressing means for pressing and holding the laser diode through the cap portion so as to be movable.   An optical pickup device comprising the laser diode optical axis adjusting structure according to claim 1.

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